There is no single duration that predicts how much a closed vehicle body will warm in the sun. Body construction, insulation, colour, sun angle, wind, unit status and load affect the result. Use measurements from your own operation for planning.
Record one waiting trial. Keep ambient conditions, shade or direct sun, wait start and end, door openings, refrigeration unit status and load sensor readings on the same timeline. If product measurements are taken, record the instrument and measurement point too.
Run the trial with a representative load and recommended operating setup; do not put product safety at risk by testing live goods outside the quality procedure. Compare records from different parking and stop conditions.
Add the observed waiting condition, approved stopping location and alarm contact to the route plan. Parking in shade or keeping refrigeration running may help, but actual performance needs verification for the vehicle and operation.
